So I have a pretty generic logging statement after a request:
try:
r = requests.get(testUrl, timeout=10.0)
except Exception, err:
logger.error({"message": err.message})
This works great for everything I've thrown at it except TimeoutError. When the request times out the err I get back is a tuple that it tries and fails to serialize.
My question is how do I catch just this one type of error? For starters TimeoutError is not something I have access to. I have tried adding from exceptions import * but with no luck. I've also tried importing OSError because the docs say TimeoutError is a subclass, but I was unable to access TimeoutError after importing OSError.
TimeoutError docs
I plan to either list my exceptions in order:
except TimeoutError, err:
#handle this specific error
except Exception, err:
#handle all other errors
or just check for type:
except Exception, err:
if isinstance(err, TimeoutError):
#handle specific error
#handle all other errors
Python 2.7.3 & Django 1.5
You can handle requests.Timeout exception:
try:
r = requests.get(testUrl, timeout=10.0)
except requests.Timeout as err:
logger.error({"message": err.message})
except requests.RequestException as err:
# handle other errors
Example:
>>> import requests
>>> url = "http://httpbin.org/delay/2"
>>> try:
... r = requests.get(url, timeout=1)
... except requests.Timeout as err:
... print(err.message)
...
HTTPConnectionPool(host='httpbin.org', port=80): Read timed out. (read timeout=1)
Related
I have 3 procedures to execute in a Oracle DB accessed via a python script. However, instead of running them sequentially, I would like to run them in parallel. How can I achieve this?
def main():
try:
myconnection_to_a_db.cursor().execute('BEGIN MYPACKAGE1.startProcess; END;')
except Exception as e:
logging.exception(e)
try:
myconnection_to_a_db.cursor().execute('BEGIN MYPACKAGE2.startProcess; END;')
except Exception as e:
logging.exception(e)
try:
myconnection_to_a_db.cursor().execute('BEGIN MYPACKAGE3.startProcess; END;')
except Exception as e:
logging.exception(e)
I'm using the requests module with max_retries option. I would like to catch the exceptions only related to timeouts and slow replies:
import requests
from requests.exceptions import ConnectTimeout, Timeout
URL = 'http://exmaple.com/sleep' # sleeps for 5 seconds before reply
with requests.Session() as s:
try:
a = requests.adapters.HTTPAdapter(max_retries=2)
s.mount('http://', a)
r = s.get(URL, timeout=1)
except (ConnectTimeout, Timeout) as err:
print('# {} - timeout'.format(URL))
But it looks like the underlying urllib3 library throws ReadTimeoutError and requests doesn't catch it and throws ConnectionError instead:
requests.exceptions.ConnectionError: HTTPConnectionPool(host='example.com', port=80): Max retries exceeded with url: /sleep (Caused by ReadTimeoutError("HTTPConnectionPool(host='example.com', port=80): Read timed out. (read timeout=1)"))
I don't want to add ConnectionError to the list because there are other exceptions that inherit from it so it would also catch those.
Is there a way to catch the original exception or perhaps all exceptions in the chain using traceback module.
Ideally, you should catch those other exceptions above ConnectionError and raise them if you want your program to throw an error.
class OtherException(requests.exceptions.ConnectionError):
pass
try:
raise OtherException('This is other exception.')
except OtherException as oe:
raise oe
except requests.exceptions.ConnectionError:
print('The error you want to catch')
You can use a similar contruct:
import traceback
import logging
try:
whatever()
except Exception as e:
logging.error(traceback.format_exc())
# Your actions here
This will almost catch everything except, for example, KeyboardInterrupt and SystemExit.
Catching those would make the script quite hard to quit.
I'm trying to raise an handle exception, catch him and and raise it again.
The problem is I can't keep that exception and cause the program to stop again when I catch the exception.
I have tried this way and a few others and have not succeeded
try:
if not (1 == 2):
raise ValueError("This is my exception")
except Exception as error:
raise ValueError(error) # Trying to throw the previous exception
Thanks in advance
If you wish to raise the exception that was caught all you need to do is use raise
try:
...
except:
raise # this will re-raise the exception that was caught
Python 3 allows you to raise an exception as the result of another exception, giving you a traceback with more information as to the root cause
try:
...
exception Exception as e:
raise CustomException('message') from e
I want to create a connection timeout exception using urlopen.
try:
urllib2.urlopen("http://example.com", timeout = 5)
except urllib2.URLError, e:
raise MyException("There was an error: %r" % e)
This is the code
I want to create a timeout that this code would bring an exception.
Thank You in advance.
You need to catch socket.timeout exception, check example below.
import urllib2
import socket
class MyException(Exception):
pass
try:
urllib2.urlopen("http://example.com", timeout = 1)
except socket.timeout, e:
# For Python 2.7
raise MyException("There was an error: %r" % e)
I strongly recommend using Requests library for making requests, it will make your life easier.
I'm using urllib.request to download files from the internet. However sometimes I get Connection Reset by Peer and I want to retry.
I tried the following, but it seems that e.errno contains socket error and not an actual errno:
while True:
try:
filename, headers = urllib.request.urlretrieve(url)
break
except IOError as e:
if e.errno != errno.ECONNRESET:
raise
except Exception as e:
raise
Any suggestions?
Well this part is not needed, first of all.
except Exception as e:
raise
And the arguments of the IOError is the type of error (socket error) and the error given to it. This error, in turn, is not the original error, but that error is in the args, so...
except IOError as e:
if e.args[1].args[0].errno != errno.ECONNRESET:
raise
Should work. I don't have a server that will reset on me, so I can't test it 100% But it works with ECONNREFUSED. :-)